dawes



(No Model.)

T. W. DAWES.

KEY HOLE GUARD. No. 390,158. Patented Sept. 25, 1888.

UNITED STATES PATENT OFFICE.

THOMAS \VM. DAWVES, OF CINCINNATI, OHIO, ASSIGNOR OF ONE-HALF TO HENRY H. LINFERT, OF SAME PLACE.

KEY HOLE GUARD.

SPECIFICATION forming part of Letters Patent No. 390,158, dated September 25, 1888.

Application filed February 18, 1888. Serial No. 26 1.515.

To all whom it may concern.-

Be it known that I, THOMAS WILLIAM DAWES, a subject of the Queen of Great Britain, and a resident of Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Key- Hole Guards, of which the following is a specifieation.

My invention relates to that class of doorlocks in which an interior guard or cover is applied to the key-hole to prevent any unlawful insertion of a key therethrough and the consequent picking or unlocking of the door from the outside.

My invention consists in the combination of a lock shell or case, a bolt, a detent-plate, a connecting link or lever, a knob-latch tumbler, suitable controlling-springs, and an automatic key-hole guard, arranged and operating as hereinafter fully described, and shown in the drawings.

Figure 1 is an elevation of a mortise lock, showing my improved key-hole guard applied thereto and in its retracted or normal position away from the key-hole. Fig. 2 is a similar view showing the guard in position covering the key-hole, the latter being in dotted lines. Fig. 3 is an inside view of the lock shown in Fig. 1, the detachable plate or cover and the guard-plate being removed, and the pins or projections on the inner face of said guardplate shown in section. Fig. 4 is a similar view to Fig. 3, but-showing the inner parts or movement of the lock in the thrown or locked position, as in Fig. 2, the pins or projections on the inner face of the guardplate being again shown in section. an elevation of the inner face or back of the detachable lock-plate, showing the key-hole guard in dotted lines and in its normal or retracted position, (the same as in Fig. 1;) and Fig. 6 is an elevation of a large rim-lock, showing the inner working parts thereof in their normal unlocked position, with the detachable plate and its accompanying key-hole guard removed, the pins or projections on the inner face of the said guard being shown in section.

A represents the case orshell of the lock, of which a is the bottom plate, and a the top or detachable plate. Openings A are made as usual in both plates a and a, for accommodat- Fig. 5 is (No model.)

ing the shouldered ends of knob-hub I) of the latchtumbler B.

b is the knob spindle or shaft passed through hub b, as customary. 5 5 0 represents a bolt comprising within itself both a latch and lock bolt, of which 0 is its head and c the plate, with the usual keynotches in its lower edge.

0 is a slot in bolt-plate c to permit it to slide 50 over the upright post or pin 0 on the bottom plate, a.

O is a projection on the upper edge of the bolt-plate, with a wide notch or space, 0, between it and the upright neck of the latch-bolt. 6 5

c is a pin on the face of said bolt-plate.

D-represents a lever pivotally connected at or about its center with bolt 0.

(Z is a pin (shown in dotted lines in Figs. 3,

4, and 6) at the upper end of lever D, and eu- 7o gaging a slot, d, in the latch-tumbler.

D is a slot in the lower end of lever D.

E is a spring suitably set-in place in the lock and controlling the latch movement, to properly shoot the latch-bolt subsequent to an ordinary retraction of it by the knob.

F represents an open detent-plate or dog, pivoted at its rear end upon the pin 0 and controlled by means of one branch of a suitable spring, F, set within the lock. The other branch of spring F exerts its force upon latchtumbler B, the purpose of which, in connection with lever D, will be fully described hereinafter.

ff are pendent projections in the opening 8 of detent-plate F, with notches e, c, and e on either side of them.

f 2 represents a pin projecting from the under side of the upper part of said detent-plate, engaging the projection 0* on the bolt-plate, 0 as shown in dotted lines in Figs. 3 and a.

G represents a sliding plate having fore and aft noses, g and g, respectively, and preferably placed in position on the outer face of detachable plate a, which latter liessuffieiently below the plane of the side walls of shell A to bring said plate G on a level or in the same plane with said side walls and permit it to reciprocate freely without coming into frictional contact with the adjacent face of the door or the material composing it or necessitating a separate recess therefor in the door.

G and G are longitudinal slots in plate a, through which pass pins H and H, cast on the backs of noses g and g, respectively, of the detent-plate. Both pins H and H are square in cross-section, excepting that the latter has a round tip, It, which engages the slot D in the lower end of lever D, as clearly shown in section in Figs. 3, 4, and 6.

h representsasplit pin inserted through an opening in the square part of pin H to properly connect the plate G with the plate a.

l and 1 represent the customary key-holes in both plates at and a, respectively.

The operation of my lock is as follows: It will be first necessary to state that the plate a and the sliding plate G of the lock are toward the outside of the door when my lock is set in place, and the shouldered bearing end of the key is made the proper length, so that it does not project beyond the outer face of plate a to come into obstructing contact with said sliding plate G when said key is inserted from the inside. \Vhcn the door is to be locked from the inside, as is usually the ease, the turning of the key raises the spring-controlled detentplate or dog and simultaneously slides the bolt (J into locking engagement with its keeperplate. Simultaneous with the advance movement of bolt 0 is the forward movement of plate G through the instrumentality of the slotted connecting link or lever D D and the engaging-pin II, which movement brings said plate over the keyhole, as clearly shown in Fig. 2, thereby forming a guard or cover therefor and effectually preventing any insertion of a key or any other opening or picking implement into the lock from the outer or other side of the door. The guard-plate G is preferably of case'hardened steel to offer all the resistance possible to a surreptitious entrance. The respective pins on both the boltplate and detent or dog occupy the positions in their respective notches (all being above named) shown in Figs. 1 and 3 when the lock. is in its normal condition that is, with the door unlocked and the parts retracted; but when the door has been locked from the inside they occupy the positions shown in Figs. 2 and 4, with the parts advanced. Pin 0" on the face of the bolt-plate in its normal position lies in the notch 0' between projcctionsf and f, the spring E bringing it to bear against projection f. Notch e is of proper width to permit a backward movement of the pin 0 therein when the bolt is to be retracted by the knob and used as an ordinary latch. Notch O on the top of the bolt-plate is also of about the same width and provided for the same purpose as notch e. WVhen the lock-bolt is advanced or shot outward,said pin 0 is in the bottom of notch c, which itjust fits, as shown in Fig. 4-, and thereby the retracting of the bolt is impossible without firstelevating the pivotal detent F. The pin 11 on the back of the guard-plate in its normal position lies snugly within the notch c of the detent F, as shown in 3, and is thereby held firmly retracted from the key-hole; but when the bolt is shot into locking position said pin assumes the position shown in Fig. 4, wherein it lies snugly within the notch e of the detent F, against the under side of pin 0 on the boltplate, and is firmly held in place against movement in either direction until the said detent or dog is raised.

The pin f on the under side of the detentplate and the projection O on the bolt-plate both serve as safety and strengthening accessories in the working of said parts to which they belong, but could be dispensed with, especially in a very light lock, as is obvious.

When the lock is to be operated or locked from the outside, the key raises the detentplate and shoots the bolt as before; but the guard-plate, being on that face of the lock through which said, key has been inserted, is now obstructed in its further and full movement by the presence of the shank of the key. Saidkey having completed its revolution in the lock, and the detent-plate being again in its normal position, the guard-plate is held at part stroke, (but just covering the keyhole, as shown in dotted lines in Fig. 2,) with the pin H in notch c and bearing against the detent projection 1'' through the exertion of spring F on the knob-tumbler.

To be able to unlock the door from the outside (a necessary precaution during the day or a temporary absence at any time) by the proper person, the knob is turned a partial revolution in a reverse direction to that usual in the ordinary latch movement, thereby depressing its branch of spring F and moving the lower slotted end of link or lever D D backward, and causing a simultaneous retraction of the guard-plate from over the keyhole without moving or otherwise disturbing the bolt in the least. The key'hole is now open and ready for the insertion of the key,

which, if it be the true one--that is, the one that properly fits the key-hole and lock-will open the door; but if the key is a false one and does not fit the lock, or is a thin wire picking implement or skeleton-key fitting the key-hole loosely, it will, on the turning back of the knob and on its being turned, or on such tamperi ng, raise the detent-plate out of engagement with the guard-plate, as is obvious, and on its withdrawal permit the now liberated guard-plate to shoot forward full stroke, efi'ectually covering the keyhole against further entrance from the outside, even with the proper key, as the guardplate and detent would then be in the same relative engaging positions as when the door is locked from the inside. Spring F brings the guard plate back to position over the key-holeon the withdrawal of the key from the outside and holds it so until the knob is turned backward, and for the purpose stated.

The lock shown in Fig. 6 embraces in its construction, in addition to the parts stated in connection with the lock shown in the other views, a pivotal arm, J. A projection, (.3 is

again present therein on the upper edge of the bolt-plate and so also is a pin, f, on the under side of the detent-plate; but instead of the pin f 2 engaging projection 0 as before, it engages 5 a slot,j, (shown in dotted lines,) in the free end of said pivotal arm J. A projeotiomj, on the lower edge of arm J engages the projection O on the bolt-plate, and thereby serves as a supplemental stop or an auxiliary for the pin 0 w and projections fand fin the event of the look being a very large or heavy one. The pivotal lever or arm J operates simultaneous with the detent-plate by reason of the coupling-pin f" engaging the slotj, as before stated.

I claim-- 1. The combination, with springdetent F, having pin f and the look-bolt having projeetion 0 of a slotted pivotal arm, Jj, slotted leverDD, and keyhole guard G, substantially as herein set forth.

2. In a door-lock, the combination of shell or case A a a, lock-bolt O c, detent-plate Ff f, lever or link D D d, knob-latch tumbler B b (1, suitable controlling-springs, E F, and an automatic key-hole guard, G H H, connected, 25 arranged, and operating substantially as herein set forth.

' In testimony of which invention I have hereunto set my hand.

THOMAS WM. DAWES.

IVitnesses:

JOHN E. J oNEs, H. LINFER'I. 

